Apparatus for the manufacture of concrete pipe



Feb. 6', 1940. 2,189,071

APPARATUS FOR THE MANUFACTURE OF CONCRETE PIPE i G. w. KOPP 2Sheets-Sheet 1 mm NM mN 0 @M "U T mw L wt 5 s 5 a .A rm k m W n n t n vzFeb. 6, 1940. s. w. KOPP APPARATUS FOR THE MANUFACTURE OF CONCRETE FIFEFiled Oct. 21, 1936 2 Sheets-Sheet 2 by centrifugal processes.

of myimproved mold is that itcan bestripped Patented Feb. 6, 1940 IAPPARATUS ort THE MANUFACTURE OF oononn'rn PIPE George 'Kopp,Hicksville, N. Y.

Application October 21,

v :15 Claims.

This invention relates to improvements in apparatus for making concretepipe by centrifugal processes.

Large amounts of concrete pipe, both plain and reinforced, aresuccessfully made by such processes. The molds are .filled with concreteand rotated by machines which cause the concrete to be formed into apipe in a very short period of time. It is a long time after the pipeand 'mold are removed from the machine, however, before the moldcjan -bestrippedjfmm the" pipe and used again. f r I mold is lined with a thinlayer of wax beforebeing filled with concrete. .Afte r a pipe has beenformed,-the mold is put .in a steamheated kiln which curies the concreteand melts the wax so that the pipef i s not" tight in the mold,and'the'mold can be removed from the pipe, cleaned, and prepared for useagain. Large, pipes remain in the kiln for many hours and each moldcantherefore be used only onceor twice a day. This makes a large numberof molds necessaryand materiallyincreases the cost of the pipe byrequiring excessive capital investment in molds and kiln equipment. l fIt is an object of thisinvention to provide improved mold equipment formaking concrete pipe One of the advantages from the pipe immediatelyafter it comes from the mold-rotating machine andhefore the .pipe hasbeen cured. This makes it possible to put the mold back into use on themachine without hereof v delay. I

The economicadvantages of the new design are found in the greatreduction in capital investment from that required forthe .solid oronepiece forms of the usualtype, saving of fuel necessaryto generatesteam .for curing, the saving of expense for wax, the much lesskilnequipment, required, and a general speeding up of production. Otherfeatures of the invention relate to the use of the same mold for pipesof diiferent size by changing an inner shell which holds the concrete;to the support of the concrete pipes while they are being cured; and tothe retention of moisture in the mold during the spinning opera-, tion.1

Other objects, features and advantages of the. invention will appear orbe. pointed out as the specificationproceeds. I I I In the accompan'ngdrawingsflforming part N Fig. l is a diagrammatic view of apparatusfor making concrete pipe by a centrifugal process;

1936, Serial No. 106,747

Fig. 2 is a longitudinal-sectional view through a moldmade in accordancewith this invention;

' Fig. 3 is an enlarged transverse sectional view taken on the line 3-3of Fig. 2; I Fig. 4 is an enlarged fragmentary, transverse sectionalviewtaken on the line 4-4 of Fig. -2; Fig. 5 is a' bottom plan view ofthe seam cover plate. on a reduced scale; and K Fig. dis a reduced-scalediagram illustrating the operation'of the invention.

Apparatus for making centrifugal pipe is shown diagrammatically in Fig.l, and comprises a mold ll having a running ring l2 by which one end. ofthem'o-ld is supported from rollers I3. The other end of they mold H hasa similar ring M which maybe supported on rollers, or held in a chuck l5of the spinning and troweling machine. The chuck l5 ,is carried by ashaft ll journaled in afbearing [Band driven through speed reductiongearing" I9 bya motor 20. V

Concreteis put into the mold ll by a trough 22, the end portion of whichis shown to the right of the moldin Fig. 1. The trough enters the moldand extends forthe full length of the mold After being pushed all of theway into .the mold the trough is rotated and dumps the concrete which itcontains .into the mold.- The trough is then moved into a position whereone of its edges bears against the concrete as a trowel to spread itevenly fand'dress its inside surface. The mechanism for moving thetrough Z2 isnot shown in Fig. 1 because it is not necessary tov acomplete understanding of this invention.

The mold l I may be constructed as shown in Fig. 2. Running rings I2 andM are rigidly connected to opposite ends of longitudinal structuralmembers comprising channels 25. These channels are angularly spacedaround the rings [2, l4 and are fastened to the rings by screwsZ'lextending through endplates 28welded to the ends of the channels. Thescrews 2! thread into the sides of therunning rings. designed to haveone end always supported by a chuck, the running ring Mrnay be replacedwith an end casting. of smaller diameter than the running ring forinsertion inthe jaws of a chuck. The runningrings l2 and M are, solid.In moldshaving running rings split to permit'the mold to On small-sizemolds nected to the channels by angles 32 prevent the channels frombeing bowed by centrifugal force when the 'mold is spinning.

An end member 34 is recessed into a face of the running ring I 2 andwelded to that ring. The running rings I2 and I4, spigot end ring 29,channels 25, hoops 3|, end member 34, and their respective fasteningscomprise a rigid frame which is the runner or carrier form of theimproved mold shown in the drawings.

The channels 25 are made thicker at spaced points along their length bywelding nuts 36 to the webs of the channels. channels in alinement withthe holes through the nuts 36 are tapped to receive pressure screws 38.The end member 34 has threaded holes in line with the channels 25 forreceiving pressure screws 38, which may be of somewhat smaller size thanthe pressure screws 38.

An inner form or shell 42 is constructed of resilient sheet metal orthin plate, andit is this inner form42 that holds the'concrete. Theinner form 42 is split and has edges 43 abutting along a longitudinalseam 44, shown at the bottom of. the form in Fig. 3.

A cover plate 46 is connected to the shell 42 by rivets 41, 48 (Figs. 3and 4) along one side of the seam 44 and this cover plate extends acrossthe seam to prevent the escape of water from inside the shell when theform is rotating. 'That side of the cover plate 46 which is not rivetedto the shell 42 isv held against the shell by buttons 50 (Fig. 4) whichhave stems with reduced ends threaded into the shell. The stems 5|extend through slots 52 in the cover plate 46. These slots are bestshown in Fig. 5. The cover plate is free to slide circumferentially withrespect to the buttons 58. v I

Referring again to Figs. 2' and 3, the shell 42 has lugs 55 riveted toit close to the pressure screws 38. A portion of each lug 55 is spacedfrom the surface of the shell 42 and has a slot through which thecooperating pressure screw 38 extends. Each of the pressurescrewshas ablock 51 pinned or otherwise secured to its inner end. These blocks 57pull against the lugs 55 to expand the shell 42 when the pressure screwsare turned in a direction to back them away from the shell. When' thepressure screws are turned the other way, the blocks 51 serve. toincrease the area of contact for'the pressure, screws 38 against theshell. The pressure screws are in effect means reacting between thecarrier form and the inner shell to hold the inner shell to asubstantially circular contour and to prevent distortion of the innershell by centrifugal force when the mold is being turned during thecentrifugal operation rf forming a pipe within the shell.

The shell 42 can be removed from the carrier form by relaxing thepressureof the screws 38 and then causin relative rotation of the shell42 and carrier form so that the screws 38 move beyond the ends of theslots in the lugs and leave the shell free to move axially out of thecarrier frame; Inner forms or shells of different diameter can be put'inthe outer or carrier form in place of the shell 42. The limits on theshell sizes which can be accommodated in the carrier form shown in thedrawing depends upon the inside diameter of the running rings I2, I 4and upon the length of the pressure screws 38. i A centering ring 59fits within the spigot end of the shell 42. to permit access to theinside of the mold for measuring. With large size molds using a wetHoles through the This ring is preferably annular mix, the centeringring 59 is replaced with a solid disk to prevent water from beingthrown-out of the mold.

An end former ring or pallet 6| fits into the bell end of the shell 42and has a shoulder abutting against the end of the shell. The' pallet 6|is firmly clamped in the shell when the pressure screws 38' are turneddown into contact with the shell, but further insurance againstdisplace,- ment of the pallet is obtained by holding a clamping ring 63against the end face of the pallet.

The clamping ring 63 is held against the end member 34 and the pallet 6|by wedges 65 driven through pins-86. These pins extend through the endmember 34, and the wedges 65 provide a quickermeans for fastening andunfastenin'g the clamping ring than if bolts were used in place of thepins 66.

rivets 48 hold the plate 46 against the shell 42 on v one side of theseam and the buttons 50 hold the plate against the shell .onthe otherside of the seam. As the shell is pulled away from the pipe it is, ofcourse, necessary for the edges of the seam 44 to move apart, and suchmovement 'is possible because of the fact .that thestems 5| of thebuttons extend through slots 52 which permit relative movementof theplate 46 and the'stems 5|. 'I'he cover plate 46 .is omitted from Fig. 6in order to make the diagram clearer andt'o show. the separation of theseam edges. v v

After the pressure screws 38 along'fthe seam 44 have been operated topull the adjacent portions Y of the shell 42 away from the pipe'68, thepressure screws along the two channels 25'next n'earest'to the seam 44are backed away, from the pipev to g pull more area of the shell 42..out of contact with the pipe. v

As each pressure screw 38is operated to pull the portion of the shellbeneath it. away from the pipe88, the stiffness of the shell causes itto pull away from the pipe over considerable area beyond that screw sothat after. the pressure screws along the seam and those along thenextchannel on each side of the seam have been operated to pull theshell 42 away from the pipe 68, more than half of the surface of theshell is outof contact with the pipe and the mold can be freely removedfrom r the pipe unless stuck to the pipe.

If the shell sticks to the pipe; more pressure screws can be backed awayfrom the pipe to pull the shell loose, but such sticking of the pipe andshell is not ordinarily encountered,v and'with mixe or molds where itdoes occur it. can be avoided by greasing the insideisurface of theshelljbefore filling it with concrete.

The mold is preferably stripped from the pipe with the pipein an uprightposition and the; pallet 6| at the, lower end of the pipe. The clamp--ing ring 63 is removed before the mold and pipe are turned upright andthe mold is then lowered to rest the pallet on .some supporting surface.

The pressure screws 38 are operated to' loosen the shell 42 from thepipe in the manneri'already described. The backing-01f ofthe screws 38'.re;

leases the pallet 6 I, and since the pallet isremovablelongitudinallythe mold can be lifted from the pipe, leaving thepiperesti-ng on the-pallet, which serves. asasupport for thefreshlytmade pipewhen placed in the curing room. Thus-the entire mold,

with the-exception oi the pallet, is removed as a unit from the pipe,and the mold is made ready to use again immediately by returning thepressure screws to their original positions and replacing the pallet. Anew pallet .isput :on the mold forcma'lcing the nextrsection of .pipebecause the curing operation requires a substantial lengthof means onthe frameadapted to connect with the split inner form and operable topull at least a part of .said inner form away from the surface of a pipetorfacilitate stripping of the-form from theapipe.

2. Improvements informs for the manufacture, centrifugally, of concretepipe or the like,

comprising a split sheet metal inner form surrounded by a rigid rrunningform with bolts extending between the forms, and connections be.

tween the bolts and inner form for spreading theinner form to strip itfrom a pipe.

3. A form for making concrete pipe or the like by a centrifugal process,said form comprising a split, resilient, inner form in which theconcrete is held during spinning operation, a rigid, outer form adaptedto be supported by the spinning into contact with the outside of theinner shell apparatus, connecting means between the inner and outerforms for expanding the inner form to pull it away from the surface of apipe made in said inner form, the connecting means in-' cluding lugs onthe outside of the inner form,

and screws held by said lugs and extending through the outer form.

4. A form for the manufacture, centrifugally, of concrete pipe or thelike, comprising a resilient inner shell for holding the concrete, saidinner shell having abutting edges forming a seam lengthwise of the innershell, a frame surrounding and spaced from the inner shell, a pluralityof pressure screws extending through the frame at pointsf spacedlengthwise of and angularly around the shell to prevent any substantialdistortion ofthe shell by centrifugal force, and lugs on the outside ofthe shell in positions to be pulled toward the frame to expand the shelland strip it from the pipe when the screws are turned in one direction.

5. A form for themanufacture, centrifugally, of concrete pipe or thelike, comprising a resilient inner; shell for holding the concrete, saidinner she-ll having abutting edges forming a seam lengthwise of theinner shell, a frame surrounding and spaced from the inner shell, saidframe including end rings connected by a number of angularly-spaced,longitudinal structural members, screws-extending through each of saidmembers at spaced points along its length and into This invention hasbeen described in conneccontact with the resilient inner :shell "to hold:it against distortion by centrifugal force, and lugs secured to theshell under each :of the. screws in position to be pu lled outward whenthe screw is turned in :a direction to back it away from the shell. h

6. A mold for the manufacture of concrete pipe at the like by thecentrifugal process, including combination .za carrier "form adapted to.be rotated, a split shell in the carrier form for holding the.concrete, an end former ring detachably held at one end of the shell,and

means :for stripping the mold from a :pipe including devices on thecarrier form operable to release the shell from the pipe whenthe mold isin an upright position with the former ring :un-

.der the lower end of the pipe, said former ring serving as a support onwhich the pipe can rest during the curing operation.

7. Apparatus for the centrifugal manufacture ner form, an innermoldfcarried in "the runner vform and. adapted :to hold the concrete,said inher mold-being expansible radially of the pipe to strip-said:mold from .the pipe, :m-eanson therun- .ner'iorm operable to cause suchexpansiblemovement of the inner mold, and a pallet at one end of theinner mold )for forming one end of the pipe, said pallet beinglongitudinally releasable from the :mold so that the pipe :can rest onthe pallet after the mold has been stripped from the pipe with the pipein an upright position.

'8. Improvements in molds for manufacturing, 'centr-ifugally, concretepipe or the like, comprisby a centrifugal process, comprising a runnerform with longitudinally extending frame members angularly spaced aroundthe form, a split shell. within the runner form, pressure screwsthreaded through the frame members at points along the length of theshell and extending radiof concrete, pipe or the like, including arunally intocontact with the shell to hold saidshell to a circularcontour and hold the seam edges in substantial abutment, and a coverplate over theseam to prevent the escape of water from within the shellduring a spinning operation.

1 10. A mold for making concrete pipe or the like by a centrifugalprocess, comprising a run- -ner form with longitudinally extending framemembers angularly spaced around the form, a split shell within therunner form, lugs attached to the shell and having portions spaced fromsaid shell and with slots extending circumferentially with respect tosaid shell, means carried by the frame members and extending throughsaid slots to hold the shell against axial movement in the runner form,the shell being axially removable from the runner form by causing reli yf ative rotary movement of the shell and form to release the lugs fromthe means extending through the slots in the lugs, said means beingradially adjustable toward and from the shell toaccommodate a shell. ofdifferent size within the runner form. I

11 A form for the centrifugal manufactureof concrete pipe or the like,said form comprising a rigid outer frame structure having one orv more,I

running rings, a split inner shell within the outer frame structure forholding the concrete during the spinning operation, and means 'forexpanding carrier form, and means on the carrier form which contact withthe split mold at several angularly spaced points around itsoutside'surface to hold the mold closedand substantially cylindrical inshape during the centrifugal operation of forming a pipe within themold, said means reacting between the 'carrier form and the split moldand being movable with respect to the carrier form to permit the mold tobe stripped from the pipe.

13. A form for the manufacture, centrifugally,

of concrete pipe or the like, comprising a one piece, sheet metal innershell for holding the concrete, said inner shell having'longitudinallyextending edges movable circumferentially with respect to one another toexpand the inner shell when a pipe is to be removed from the mold, aframe surrounding and spaced from the sheet metal inner shell, aplurality of pressure devices on the frame extending into contact withthe outside of the sheet metal shell at points spaced lengthwise of andangularly around the shellto give the shell a substantially circularcontour and to prevent any substantialdistortion of the shellcentrifugal force, ndlugs on the outside bf,

the shell m positions to be pulled toward the 1' frame to expand theshell andstrip it from the pipe when the pressure devices are moved inone direction. 1

14. A composite form for the centrifugal manufacture of concrete pipe orthe like, said form comprising" a rigid outer frame structure having oneor more running rings, a'split inner shell within the outer framestructure for holding the means holding the'outer' frame and inner shell10 concrete during the spinning operation,- and in assembled relation,said means including de- I vices carried by the outer frame andextending inward to the split inner shell and operable to expand thesplit inner shell while the rigid outer frame remains unaltered.

, 15. A composite form for the centrifugal man'- ufacture of, concretepipe or the like, said'form comprising a rigid outer frame structurehaving one or more running rings, a resilient inner shell within theouter frame structure for holding the concrete during the spinningoperation, said resilient shell being split'lengthwise to permit it toopen when a pipe is to be removed from the inner shell in assembledrelation, said means including several devices reacting between the outapart points around the peripheral surface of the resilient inner shell,to give said resilient shell "25 mold, and means holding the outer frameand.

er frame and the resilient inner shell at spaced a substantiallycircularcontour and to prevent any substantial distortion'of the shellby centrifugal force.

I GEORGE W. KOPP;

